1. Field of the Invention
The present invention relates to an integrated circuit assembly.
2. Background Information
Computer systems typically contain one or more microprocessors that perform various tasks in accordance with instructions and data. The instructions and data can be transmitted, stored and retrieved from other devices such as a dynamic random access memory (DRAM) integrated circuit or a hard disk drive.
The microprocessor is typically fabricated as a single integrated circuit that is assembled into a package. The package may be soldered to a printed circuit board commonly referred to as a motherboard. Likewise, memory devices may be formed in separate integrated circuits that are packaged and mounted to the motherboard. Separating the microprocessor and the memory circuits simplifies the design, replacement and repair of the two components.
The microprocessor typically contains core logic memory circuits that receive input signals and provide output signals. The microprocessor may also have driver and buffer circuits that provide an interface between the logic/memory circuits and other devices coupled to the processor. It has been found that the driver circuits may create electrical noise in the power and ground busses of the integrated circuit when switching states. The noise may affect the operation of the logic/memory circuits of the microprocessor.
There have been developed integrated circuits with on-board filtering capacitors which reduce the noise created by the driver circuits. On-board capacitors increase the complexity and the cost of mass producing the microprocessor. It would therefore be desirable to provide an integrated circuit assembly that would isolate the driver circuits from the core logic/memory circuits of a microprocessor.
A microprocessor will typically contain a clock circuit(s) that is connected to the logic/memory circuits. The clock circuit is typically constructed with the same fabrication process as the other logic/memory circuits of the processor. It is desirable to reduce the line widths, etc. of an integrated circuit to increase the transistor density of the circuit. Unfortunately, improving transistor density may also reduce the robustness of the clock circuit, introducing additional skew and other undesirable signal conditions. It would be desirable to separate the clock circuit from the logic/memory circuit of the processor.
The input/output (I/O) signals, and power/ground are provided to the microprocessor or through die pads located on an external surface of the integrated circuit. The die pads are typically connected to a substrate or interposer of the integrated circuit package. The substrate/interposer is mounted to a printed circuit board such as the motherboard of a computer.
There have been developed integrated circuit packages which connect the integrated circuit to the substrate/interposer with a plurality of solder bumps with a process commonly referred to as controlled collapsed chip connection (C4). The solder bumps are located within a two-dimensional array that extends across a bottom surface of the integrated circuit. The substrate/interposer includes routing traces and vias that connect the solder bumps to contacts that are attached to the printed circuit board. The substrate/interposer xe2x80x9cfans-outxe2x80x9d the relatively small die pad pitch of the integrated circuit to the larger contact pad pitch of the printed circuit board. It would be desirable to utilize the substrate/interposer for functions other than fanning out the signals of the integrated circuit.
One embodiment of the present invention is an integrated circuit assembly that includes an integrated circuit which is connected to an interposer. The integrated circuit may include a logic circuit which generates an output signal. The interposer may include a driver circuit that regenerates the output signal.